DESCRIPTION (from the application): Telomeres are the functional units on chromosome ends that provide stability to eukaryotic chromosomes. Telomere length is maintained by an equilibrium of shortening and lengthening activities. Evidence has accumulated over the past ten years that show that telomeres and telomerase are involved in cellular senescence and in cancer. Most of the major publications in the past two years since the first (1999) Cold Spring Harbor laboratory meeting on telomeres and telomerase, were first described as unpublished results at the CSH telomere and telomerase meeting. These recent experiments indicate that the loss of telomere function may signal cell cycle arrest and apoptosis through DNA damage checkpoint mechanisms. Additional evidence now indicated that the inhibition of telomerase will inhibit the growth of cancer cells. In addition there have been major advances in telomerase biochemistry and in understanding the components that make up the terminal telomere protein complex. This new research has generated significant interest in telomere biology in a variety of fields including molecular biology, human genetics, aging and cancer. The format of Cold Spring Harbor meetings, where all talks are chosen from submitted abstracts, maximizes the opportunity of new researchers and young investigators to present their most recent unpublished work. The last meeting had uniformly high attendance from an international group of researchers. The platform presentations at this past meeting were uniformly high and there was participation from most of the 266 people who attended. Having established at the last meeting that this telomere meeting is an excellent forum for free discussion of ideas, we anticipate that the future meetings will be well attended.